Here 91 just dropped back to $2.79 from $3.15! I have to run Premium in three of my vehicles so I know the pain of paying for 91.

In reality the .20 more per gallon on a 21 gallon fill up is only $4.20. If you burn through a tank a week, is it worth a few bucks to possibly damage your engine? Have one less Caramel Frapachino half-caf, mocha swirl a week and save your engine!

This is one of those "pay to play" things- It's really not a good idea to test out if 89 will work.
It might be just fine for a while- Find the right combination of weather and gas- and you might be paying for an engine rebuild...Just that fast.

@ 2-3 bucks more a tank (max)- You'd have to fill up about 1000 times or more before you'd save enuf money to pay for an engine rebuild....

the trd website claims you can run lower than 91 octane in a supercharged application, but "performance will be reduced" also as a side note, the VVT-i system in our trucks DOES perform better with higher octane fuels ( not just better gas mileage, but better performace) but you can run any octane in a NA engine (ive had both...)

Do you really get better gas mileage or are your driving habits a little different when running different fuels?

I filled up yesterday with 87octane for 2.65 a gallon for a total of 45.05.
For 91octane it would have cost 50.15 to fill up. Would 10 more miles a tank make up that 5 bucks? I fill up once a week usually and that would be an extra 20 bucks a month...I just dont really know if it would be worth it

the trd website claims you can run lower than 91 octane in a supercharged application, but "performance will be reduced" also as a side note, the VVT-i system in our trucks DOES perform better with higher octane fuels ( not just better gas mileage, but better performace) but you can run any octane in a NA engine (ive had both...)

Click to expand...

I am sorry, but I disagree with this statement.
Simply put, VVT (Variable Valve Timing) systems are meant to increase efficiency in engines via managing 'pumping losses' while maintaining 'normal' engine performance values, not to increase performance.
This is done by decreasing 'cylinder pressure' (ie-shortening the compression cycle) via 'valve open' durations during periods of low load (where most vehicles are normally operated) & returning to the 'normal valve duration cycle' of an engine, when under load.
The trade-off for the 'efficiency state' of VVT is a loss of engine torque, as that is what occurs with reduced cylinder pressures. However, this operation is managed electronically & happens so quickly that any torque loss is 'transparent' to the vehicle operator.
The only performance gains that VVT technology provides is that the Manufacterers did not have to completely dog down engines to meet Government C.A.F.E standards for efficiency for the vehicles they sell.

As I have stated previously, the only time you would REQUIRE premium fuel is when you INCREASE cylinder pressure one way or another (supercharger, turbocharger, high compression pistons, etc...)

The only benight of higher octane in an application without boost or a high compression ratio is potentially higher grade fuels have more additives. Other than this, premium fuel is LESS VOLITAL than regular fuel, and also generally has a lower energy content than regular fuel, due in part to higher octane is generally created by mixing more ethanol into the fuel. In high performance engines that run the risk of pre detonation the advantage is that you can a higher degree of spark advance to make a bit more power. Converaly, modern car with a nock sensor will retard timing when it notices knocking occuring. Your consumer brains are progred to think 93>89 which =better. This is not true, it is a question of what makes sense in what application. If you are putting premium gas in a stock Tacoma in hopes that your truck will last 10k more, you are straight up pissing away $10 into the petroleum machine every time you fill up. Over the life of the truck you will spend more doing that that the cost of a new truck.